The author cites Peter Thiel’s interview question as a working diagnostic for whether someone has actually done first-principles thinking: “‘What important truth do very few people agree with you on?’ That’s basically asking: where have you done first principles thinking that led you somewhere different from the crowd?” The mechanism is forensic: independent reasoning produces conclusions that diverge from consensus on at least some points; if your full belief set tracks the consensus, you probably haven’t done the decomposition work, regardless of how confident or articulate you are about the conclusions.
The author’s diagnosis: “Most people can’t answer it. Because most people don’t think from first principles. They think from analogy. So they end up with the same conclusions as everyone else.” This is the inversion of First-principles thinking is uncomfortable because it transfers responsibility — analogy outsources blame to 'best practices' — accepting the responsibility tax produces uncommon conclusions as a side effect, so the absence of uncommon conclusions is evidence the tax was never paid. Pairs with Reasoning by analogy has a ceiling — you can never get beyond what already exists by copying what already exists in a falsifiable way: analogy can only produce reachable conclusions inside the existing solution space, so a portfolio of beliefs entirely inside that space is signal that the reasoner never escaped it. The test is not “do you have a contrarian take?” (which can be performance) but “have you done the work that would naturally produce one?”